Nucleating agents are usually employed as processing aids primarily to accelerate crystallization from a melt.
Acceleration of crystallization results in faster molding cycles, which of course means greater productivity in molding operations. Generally, nucleating agents are believed to provide sites for crystallization of molten polyamide. However, nucleating agents are also identified by their ability to increase tensile strength and stiffness of the polyamide, decrease elongation, and decrease mold shrinkage. The term "nucleating agent" as employed herein, is meant to denote those additives which increase tensile strength and decrease tensile elongation and mold shrinkage.
A deficiency of many nucleating agents is that they also significantly lower the Izod impact strength of the resin compared with that of the polyamide without nucleating agent. In contrast, the nucleating agents employed herein provide nucleating properties to polyamides but do not result in a significant lowering of Izod impact strength.